Sub-miniature polar relay



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Jan. 27, 1959 N. CURRY 2,871,312

SUB-MINIATURE POLAR RELAY .7

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INVENTOR. TEWQW United States Patent SUB-MINIATURE POLAR RELAY Neil Curry, Van Nuys, Calif.

. Application July 23, 1956, Serial No. 599,627

4 Claims. (Cl. 200-93) This invention relates to a sub-miniature polar relay of which the following is a specification.

At the present time, most miniature relays are merely scaled-down versions of larger single current relays. This method of achieving miniaturization by scaling down a conventional single current relay adversely affects a number of important performance characteristics which are required of a relay, including contact size, contact pressures, sensitivity, and vibration and shock resistance.

It is, therefore, an object of my invention to provide a novel sub-miniature polar relay having output and performance characteristics comparable to those of larger relays, and with speed and frequency response superior to those of larger relays. Another object of my invention is the provision of a miniature relay which is of the polar type having two magnetic paths, one for a permanent magnetic flux and the other for the magnetic flux created by the fiow of current through the relay coil. In a conventional single current relay, the force acting on the armature is equal to the square of the fiux. In my polar relay, the force acting on the armature is equal to the product of the permanent magnetic flux and the current flux. It is thus possible to provide a higher output than from a convention l single current relay while substantially reducing the relay size.

Relays of the character of that under consideration here are utilized in aircraft and similar applications and are subjected to high G loads, excessive vibration and the like.

An additional object of my invention is the provision of a relay of the aforementioned character which is particularly resistant to high G loads, excessive vibration and the like.

Another object of my invention is the provision of a suspension system for the armature of a sub-miniature relay which includes a spring wire mount which acts both as a cantilever support and as an electric current carrying means. The mount is short in length and is mounted parallel to the axis of rotation of the armature to assure greater stability under shock and vibration.

A further object .of my invention is the provision of adjustment means for the armature of said relay, said adjustment means including an adjustment block mounted for movement with respect to the fixed contacts of said relay to carry portions of said armature toward or away from said fixed contacts. The simple construction of the adjustment means facilitates adjustment of the armature in a manner to be described hereinbelow.

in conventional relays of the character of that under consideration here, the adjustment of the movable contacts on the armature with respect to the fixed contacts is accomplished by bending and the like processes and is a time-consuming and tedious operation.

An additional object of my invention is the provision of a relay characterized by the ease with which the movable contacts thereof can be adjusted with respect to the fixedcontacts.

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Another object of my invention is the provision of a polarized relay wherein the armature and fixed contacts of the relay can be readily assembled in operative relationship with the magnet and pole pieces of the relay so that adjustment of the movable with respect to the fixed contacts of the relay can be accomplished prior to the assembly of these components with the remainder of the relay.

During prolonged use of relays, the contacts naturally become worn and, in conventional relays, it is frequently necessary to discard the entire relay since the unitary assembly of the component parts thereof prevents the replacement of the contacts.

A further object of my invention is the provision of a polarized, sub-miniature relay which incorporates a frame member in which the armature and fixed contacts are demountably assembled so that when the contacts become worn or adjustment of the armature is necessary, the armature and fixed contacts can be readily removed from operative relationship with the frame member.

A further object of my invention is the provision of a sub-miniature relay which is usea ble for substantially any switching or power application in which the polarity of the current supplied to the relay does not change. In addition, it is applicable to any switching or power application requiring the use of a polar relay with its inherent polarity sensing arrangement. The relay of my invention is capable of use as a polarized vibrator, or a D. C. or A. C. chopper and when used with a conventional vibrator transformer, the input D. C. voltage may be inverted for A. C. outputs or rectified for higher voltage application.

A further object of my invention is the provision of a sub-miniature relay of the aforementioned character wherein the above referred to spring wire mount is supported in bushings in the insulator mounting plate or wherein the spring wire mount or yoke is actually cast into a unitary one-piece plastic insulator plate.

An additional object of my invention is the provision of auxiliary springs of the cantilever or compression type which I utilize to bias the conductive armature of the relay into normally closed positions, the compression spring being readily adjustable to determine the pressure of the contacts on each other when disposed in said normally closed positions.

Other objects and advantages of my invention will be apparent from the following specification and accompanyina drawings which are for the purpose of illustration only and in which:

Fig. 1 is a vertical, sectional view of a relay constructed in accordance with the teachings of my invention;

Fig. 2 is a vertical, sectional view taken on the broken line 22 of Fig. 1;

Fig. 3 is a vertical, sectional view taken on the broken line 3-3 of Fig. 2;

Fig. 4 is an enlarged, fragmentary view showing the manner in which the contacts of the relay are demountably associated with the remainder of the relay;

Fig. 5 is a perspective view of a housing of an alternative embodiment of the relay of my invention;

Fig. 6 is a vertical, sectional view taken on the broken line 66 of Fig. 5;

Fig. 7 is a vertical, sectional view taken on the broken line 77 of Fig. 6;

Fig. 8 is an enlarged, fragmentary view taken on the broken line 8-8 of Fig. 6;

Fig. 9 is a side elevational view of an alternative embodiment of a portion of the relay of my invention;

Fig. 10 is a vertical, sectional view taken on the broken line l010 of Fig. 9;

Fig. 11 is an enlarged, fragmentary view of another embodiment of the polarized relay of my invention; and

Fig. 12 is a vertical, partly sectional view taken on the broken line 1212 of Fig. 11.

Referring to the drawings, and particularly to Figs. 1 and 2 thereof, I show a relay constructed in accordance with the teachings of my invention and constituted, generally, by a permanent magnet-coil assembly 12 and an armature-contact assembly 14, said assemblies being maintained in operative relationship by a frame 16. Y The frame 16 is, as best shown in Figs. 1 and 2 of the drawings, constituted by an elongated, substantialIy U- shaped member 18 formed from sheet metal, or the like, and disposed in inverted position so that the permanent magnet-coil assembly 12 is fixedly mounted on the bight of the U-shaped member 18, while the armature-contact assembly 14 is removably disposed upon and supported between the legs 20 of said member and further locked in position by an epoxy or other adhesive.

The permanent magnet-coil assembly includes a pair of spaced pole pieces 22 and 24, the lower ends of which are secured in openings 26 and 28 in the bight of the U-shaped frame member 18. Located centrally of the U-shaped frame member 18 and intermediate the pole pieces 22 and 24 is a permanent magnet 30 whose lower extremity extends through an opening 32 in the bight of the frame member 18.

Supported upon the upper extremities of the pole pieces 22 and 24 is a plate 34 formed from permeable magnetic material which serves as part of the flux paths of the permanent magnet-coil assembly 12, in a manner to be described in greater detail below. A coil 36 encompasses the pole piece 22 and a similar coil 38 encompasses the pole piece 24. Therefore, it is readily apparent that the components of the permanent magnet-coil assembly 12 are permanently secured to the bight of the frame member 18 so'that the permanent magnet flux pattern and the coil fiux pattern may be established thereby.

The armature-contact assembly 14 is demountably located in the frame 16 constituted by the elongated, U- shaped frame member 18 by virtue of the fact that the oppositely disposed depending legs 20 of said frame member are provided with elongated, longitudinally oriented slots 40 adapted to engage the opposite edges of a substantially rectangular, elongated insulator plate 42 which thus constitutes a mount for the armature-contact assembly and which can be readily slid into or out of operative relationship with the frame member 18 by virtue of the slots 40 formed in the oppositely disposed legs 20 thereof. Therefore, after the permanent magnet 39, the pole pieces 22 and 24 and the coils 36 and 38 have been permanently assembled upon the bight of the frame member 18, the armature-contact assembly 14 can be inserted between the legs 20 of the frame member 18 to dispose the same in operative relationship with the permament magnet-coil assembly 12. Thus, it is possible to adjust the contacts of the armature-contact assembly 14 prior to mounting the same in the frame 18 which materially reduces the time and labor involved in setting the contacts. Moreover, when the aforesaid contacts become worn, it is possible to remove the armature-contact assembly 14 from operative relationship with the frame member 18 and to install a new armature-contact assembly 14 in its stead.

An elongated, rectangular armature bar 44 is located in the space between the bight of the U-shaped frame member 18 and the insulator plate 42 and is supported in said space by means of an adjustor plate 46 which is movably mounted on the insulator plate 42 by means of adjustment screws 48 and 50. The operative connection between the adjustor plate 46 and the armature 44 is constituted by a U-shaped yoke 52 formed from spring wire, such as beryllium copper, stainless steel, or the like, and located in inverted position with the bight of the yoke spot welded or soldered in the transverse slot 54 formed in the underside of the adjustor plate 46' and .with the upper extremities of the legs of the yoke 52 located in slots 58 formed in the opposite sides of the armature 44 and spot welded or soldered therein.

The spring Wire yoke 52 has such a relatively short effective length, that is, the length of the legs of the yoke 52 between the upper surface of the adjustor plate 46 and the underside of the armature 44, that great stability under high shock and vibratory loads is achieved which prevents unwanted deflection of the armature 44 on the yoke 52 in'either lateral or longitudinal directions. Moreover, the yoke 52 acts as a cantilever spring and is disposed in a plane substantially parallel to the plane of movement of the movable armature contacts 60 and 62.

A pair of fixed contacts 64 and 66 is riveted or threadedly mounted in the insulator plate 42 for co-operation, respectively, with the contacts 60 and 62 on the armature 44.

Adjustment of the movable contacts 60 and 62 with respect to their associated fixed contacts 64 and 66 may be accomplished by appropriate rotation of the adjustment screws 48 and 50 in the insulator plate 42 to cause appropriate rotation of the adjustor plate 56 about an axis of rotation located between the adjustment screws 48 and 50. Therefore, the movable contacts 60 and 62 can alternately be moved toward or away from their associated, respective, fixed contacts 64 and 66. In this manner, the bending or other prior art expedients used to accomplish adjustment of the movable with respect to the fixed contacts of the relay is eliminated and it is readily apparent that the movable contacts 60 and 62 may be easily adjusted toward or away from their associated fixed contacts 64 and 66 while thearmature-contact assembly 14 is dismounted from operative relationship with the U-shaped frame 16 and that, after such adjustment, the armature-contact assembly 14 can readily be reinstalled in operative relationship with said frame.

In accomplishing the adjustment of the various contacts of the armature-contact assembly 14 with respect to each other, it should be noted that the threaded engagement of the fixed contacts 64 and 66 with the insulator plate 42 permits these contacts to be adjusted in said insulator plate to impart greater flexibility of adjustment to the aforesaid assembly. It should be noted at this juncture that the yoke 52, in addition to serving as the mount for the armature 44, also serves as a conductor to transmit current to the movable contacts 60 and 62.

Although it is possible to rely in some applications upon the inherent resilience of the yoke 52 to accomplish and permit movement of the armature 44 with respect to contacts 64 and 66 and the insulator plate- 42, I have found that it is occasionally desirable to provide an auxiliary or booster spring 68 which increases the sensitivity of the relay. 68 is not utilized, the loading of the movable contacts 60 and 62 is accomplished by deformation of the legs of the yoke 52 and since the legs are very short and have high spring rates, more energy is necessary to deflect the armature 44 and produce the necessary contact pressures.

By providing the auxiliary spring 68 which has a relatively low spring rate, the desired loading of the contacts can be 'much more efliciently accomplished. The auxiliary spring 68 is formed from resilient sheet material such as spring steel, beryllium copper, or the like, and includes a U-shaped end portion encompassing the adjacent end of the adjustor plate 46 and an elongated leg portion engaging the underside of the armature 44, as best shown in Figs. 1 and 3 of the drawings.

The use of the auxiliary spring 68 is only indicated when the relay 10 is applied for use as a rela which would necessitate the deformation of the legs of the yoke 52 in the aforementioned manner. In all other applications, the inherent resiliency of the legs of the yoke 52 can be relied upon to permit movement of the armature 44.

Disposed below and in spaced relationship with the In applications Where the auxiliary spring' insulator'plate 42 is a glass header plate 70 in which is hermetically sealed a plurality of terminals 72 which are soldered or otherwise connected to conductors 74 secured to the fixed contacts 64 and 66 to conductors 78 communicating with the coils 36 and 38 and to a conductor 23 which transmits current through the adjustment screws 48 and 50 to the adjustor plate 42 and thus through the yoke 52 through the armature 44 and the movable contacts 60 and 62.

A metallic flange 82 is provided around the periphery of the header plate 70 and is adapted to receive the lower extremity of a cover 84 which encompasses the permanent magnet-coil assembly 12 and the armature-contact assembly 14 and is hermetically sealed to the flange 82.

Depending upon the application of the relay 10, the

adjustment screws 48 and 50, which are threadedly engaged in the opposite ends of the adjustor plate 42, can be so adjusted as to cause one of the movable contacts 60 or 62 to engage its respective fixed contact 64 or 66 while the other pair of contacts is normally open. Of course, the relay can also be adjusted so that the armature 44 is in a normally center-stable position with all contacts normally open. The contacts will then be closed in accordance with the polarity of the current flowing through the coils 36 and 38.

By suitable adjustment of the size and preload of the yoke 52 and by adjustment of the flux pattern of the permanent magnet 30, the relay 10 can be made to operate as a magnetic latch type with the armature 44 remaining in either contact closing position to which it is moved.

With regard to the operation of the relay of my invention, it will be noted that two magnetic flux paths are provided, one for the permanent magnet 30 and one for the flux produced by current flowing through the coils 36 and 38. The flux pattern of thepermanent magnet 30 is constituted by a statically, magnetically balanced bridge made up of pole pieces 22 and 24 and the plate 34 of magnetically permeable material. When the armature 44 is centered, the static forces acting upon said armature in the permanent magnet flux pattern are balanced and counteract each other.

The flux pattern produced by operating current flowing through the coils 36 and 38 induces opposite magnetic polarity in the lower ends of the pole pieces 22 and 24 causing one end of the armature 44 to be attracted toward the adjacent pole piece while the opposite end is repelled. Resultant movement of the armature 44 causes one movable contact 60 or 62 to be moved into engagement with its associated fixed contact 64 or 66.

An alternative embodiment 90 of the relay of my invention is shown in Figs. 5 through 8 of the drawings and includes a header plate 70 having a metallic flange 82 provided upon the periphery thereof which is adapted to receive the lower extremity of a cover 84 which encompasses a permanent magnet-coil assembly 12 which is substantially identical with that of the previously de scribed embodiment of the invention and which will, therefore, not be described in further detail here. Also enclosed within the cover 84 which is, of course, hermetically sealed to the flange 82, is an armature-contact assembly 92, said armature-contact assembly being mounted in a U-shaped frame 16 constituted by a frame member 18 having oppositely disposed legs provided with slots 40 identical with those in the previously discussed embodiment of the invention.

The armature-contact assembly 92 includes a substantially rectangular, elongated insulator plate 42 which serves as a mount for the assembly and which can be readily slid into or out of operative relationship with the frame member 18 by virtue of the slots 40 and which can be temporarily located in operative relationship with said slots and against inadvertent dislodgement therefrom by the use of any desirable adhesive such as an epoxy adhesive. The advantages of prior adjustment of the armature-contact assembly and the removal thereof with ease, as in the previously discussed embodiments of my invention, are also obtainable with the relay under discussion here.

An elongated, rectangular armature, bar is disposed in spaced relationship with the insulator plate 42 and is supported in said spaced relationship by a U-shaped yoke 94 formed from spring wire, such as beryllium copper, stainless steel, or the like. The lower extremities of the legs 96 of the yoke are mounted in vertical bores 98 in bushings 100, said bushings having heads 102 and shanks 104, said shanks being located in openings 106 in the insulator 42 and swaged over to maintain them in operative relationship therewith. The lower extremities of the legs 96 of the yoke 94 are maintained in operative relationship with the. bores 98 in the bushings by means of soldering, or the like, while the upper extremities of said legs and the bight of said yoke are spot welded or swaged in a transverse U-shaped groove 108 in the armature 44.

Also mounted in a threaded bore 110 in the insulator plate 42 is an adjusting screw 112, said adjusting screw having a protuberance 114 at its upper extremity which seats a compression spring 116 and the upper extremity of said compression spring being received in a circular aperture 118 in the underside of the armature 44.

Contacts 60 and 62 are riveted or otherwise secured to the armature 44 while contacts 64 and 66, respectively, engageable with the contacts 60 and 62 are riveted or threadedly engaged in the insulator plate 42.

By the provision of the bushings 102, the effective length of the legs 96 of the yoke 94 is kept at a minimum, said effective length being the length of the leg between the tops of the bushings and the underside of the armature 44. However, the use of the bushings materially simplifies the mounting of the legs 96 in the yoke 92 in operative relationship therewith in the insulator plate 42. The compression spring 116 is utilized, of course, to adjust the contacts into closed position, as shown in the case of the contacts 60 and 64 in the present embodiment of the invention, and serves the same function as the auxiliary cantilever spring 68 previously described in revealing the previously discussed embodiment of the invention. However, in either case the auxiliary spring can be adjusted, prior to the insertion of the armaturecontact assembly 92 in operative relationship with the slots 40 in the U-shaped frame member 18, thus eliminating the delicate and painstaking operation customary in conventional relay designs.

Shown in Figs. 9 and 10 of the drawings is an armature-contact assembly 120 wherein an auxiliary brass support plate 122 is afiixed to the underside of the insulator plate 42 by means of the screw 124, or the like. Mounted in openings 126 in the support plate 122 are tubular metal bushings 128, said bushings being operatively secured in said openings by means of soldering 130, or by means of'riveting. The shanks of the bushings 128 extend upwardly through openings 132 in the insulator plate 42 and are provided with bores 134 which receive the legs 96 of the yoke 94. It is obvious that, by this method, the yoke 94 can readily be mounted in the insulator plate 42 and, moreover, that any strains imposed upon the yoke 94 will be absorbed by the support plate 122. it should also be noted that the adjustment screw 112 is threadedly engaged in the brass support plate 122.

It should also be noted that the adjusting screw in the armature-contact assembly 120 can be locked after adjustment by soldering it to the brass plate 122, while the adjusting screw 112 in the insulator plate 142 of the armature-contact assembly 92 can be locked by the use of a suitable adhesive. Furthermore, as in the case of the armature-contact assembly 92, the legs 96 of the yoke 94 are maintained in operative relationship with the bores 134 in the tubular metal bushings 128 by soldering, or the like.

Shown in Figs. 11 and 12 of the drawings is an alternative arrnature-contact assembly 140, said armaturecontact assembly 140 differing from the armature-contact assemblies previously discussed herein by virtue of the fact that the insulator plate 142 thereof is molded from a plastic, such as an alkyd resin, and the U-shaped yoke 144 is molded in the insulator 142 as it is formed. It will be noted that the conductor 146 is also molded in place on the bight of the yoke 144. Integral bosses 148 encompass the upwardly oriented legs of the yoke 144 and restrict the effective length of the legs to the relatively small space between the upper extremities of the bosses 148 and the underside of the armature 44. The armature 44 is formed with spaced bores 150 therein and the extreme upper ends of the legs of the yoke 144 can be operatively secured therein by means of soldering, spot welding, or swaging.

Therefore, the bosses 148 serve to restrict the efiective length of the legs ofthe yoke 144 and thus serve to prevent undue deflection of the armature 44 under high G loads or the like.

I thus provide by my invention a sub-miniature polarized relay which is characterized by its ability to resist vibratory and shock loads which would damage or cause the malfunctioning of much larger relays. Moreover, the relay of my invention is also characterized by the ease of adjustment of the movable with respect to the fixed contacts thereof and by the ease of assembly and disassembly of component portions of said relay.

I claim as my invention:

1. In a relay, the combination of: a U-shaped, inverted frame having a bight and depending legs provided with oppositely disposed slots; a core secured to said frame; a permanent magnet located centrally of said core; coils mounted in spaced relationship on said core; a mounting plate slidably secured in the slots in said frame; adjustment means on said mounting plate including an adjustment plate movably secured to said mounting plate; fixed contacts mounted on said mounting plate; an armature movably mounted on said plate by said adjustment means;

and movable contacts on said armature.

2, In a relay, the combination of: a core having a pair of pole pieces mounted in spaced relationship in a mutual conductor; a permanent magnet disposed closely adjacent said core to produce a permanent magnetic flux in said pole pieces; coil means disposed closely adjacent said core to produce a variable magnetic flux in said pole pieces; an armature movably mounted adjacent the ends of said pole pieces; a movable contact carried by each end of said armature; a fixed contact engageable by each of said movable contacts; means for supporting said armature for movement of said movable contacts into engagement with said fixed contacts, said supporting means comprising a spring wire having one portion attached to said armature and another portion attached to said relay, said 8 spring wire being substantially U-shaped and having its legs attached to said relay; and an adjustment plate disposed adjacent said armature having a pair of screws attached thereto on opposite sides of said spring wire,

- said spring wire being attached to said adjustment plate and said screws being individually adjustable to move said adjustment plate and cause said spring wire to move said armature to adjust the spacing of its movable contacts with respect to said fixed contacts.

3. In a relay, the combination of: a core;'a permanent magnet disposed adjacent said core to produce a permanent magnetic flux in said core; coil means disposed adjacent said core to produce a variable magnetic flux in said pole pieces; an armature mounted adjacent said core; a movable contact carried by each end of said armature; a fixed contact positioned to be engaged by each of said movable contacts; an insulator plate disposed adjacent said armature; an adjustment plate disposed between said armature and insulator plate, said adjustment plate having a pair of openings extending therethrough; a pair of adjustment screws, each of said screws extending through said insulator plate and into said adjustment plate; a substantially U-shaped spring yoke having its legs attached to said armature, the bight of said yoke extending around said adjustment plate and being attached thereto, said screws being individually movable to cause said yoke to move said armature to adjust the relative positions of said fixed and movable contacts.

4. In a relay having a pair of pole pieces and an armature mounted for reciprocal movement in respect to the magnetic flux induced in said pole pieces, said armature having a pair of movable contacts, the combination of: an insulator plate disposed adjacent said armature; a fixed contact on each end of said insulator plate adjacent each of said movable contacts; an adjustment plate disposed be tween said armature and insulator plate, said adjustment plate having a pair of openings extending therethrough; a pair of adjustment screws extending through said insulator plate and into said adjustment plate; and a substan tially U-shaped spring yoke having its legs attached to said armature, the bight of said yoke being attached to said adjustment plate and disposed between said adjustment plate and said insulator plate, said screws being individually movable to cause said yoke to move said armature to adjust the relative positions of said fixed and movable contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,606,164 Garvin Nov. 9, 1926 1,886,629 Blake Nov. 8, 1932 2,404,227 Hall July 16, 1946 2,436,224 Ogle Feb. 17, 1948 2,443,784 Bullen et al June 22, 1948 

